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Results for “SOCIAL ISOLATION”

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PubMed1999

Involvement of peripheral type of benzodiazepine receptor in social isolation stress-induced decrease in pentobarbital sleep in mice.

Our previous studies have shown that central-type benzodiazepine (BZD) receptors (CBR) and neurosteroids capable of modulating GABA(A) receptor function are involved in the decrease of pentobarbital (PB)-induced sleep caused by social isolation stress in mice. In this study, to further clarify the mechanism underlying this decrease, we investigated the possible involvement of peripheral-type BZD receptors (PBR) which play an important role in neurosteroidogenesis in PB sleep in socially isolated mice. Socially isolated mice showed significantly shorter duration of PB-induced sleep than group-housed animals. When injected intracerebroventricularly (i.c.v.), FGIN-1-27 (FGIN, 25-100 nmol), a selective PBR agonist, and PK11195 (PK, 14-28 nmol), a PBR antagonist, and pregnenolone (PREG, 15-30 nmol), a neurosteroid precursor, dose-dependently normalized the PB sleep in isolated mice without having an effect on the group-housed animals. In contrast, pregnenolone sulfate (PS, 24 nmol), an endogenous neurosteroidal negative allosteric modulator of the GABA(A) receptor, reduced PB sleep in group-housed but not isolated mice. PS, at the same dose, significantly attenuated the effects of FGIN (100 nmol), PK (28 nmol) and PREG (30 nmol) in isolated mice, while FGIN (100 nmol), PK (28 nmol) and pregnenolone (30 nmol) significantly blocked the effect of PS (24 nmol) in group-housed mice. These results suggest that the PBR-mediated decrease in the genesis of neurosteroid(s) possessing a GABA(A) receptor agonistic profile is also partly involved in the down regulation of the GABA(A) receptor following long-term social isolation and contributes to the decrease of PB-induced sleep in isolation stressed mice.

Animals↗

PubMed2004

The impact of job strain on social isolation: a longitudinal analysis of French workers.

Numerous studies have shown that work may have an impact on social identity and social functioning in the community. Since work organisation in our society has gone through some profound changes in the last few decades, it is important to study the effect of these new constraints on the social life of people and, thereby, on their health. Using data from a French longitudinal cohort study on work, health and ageing (ESTEV), this paper analyses the impact of job strain on social isolation, in a sample of 16,950 individuals who were working in 1990 and 1995. The results show that low-decision latitude was associated with a significantly higher level of social isolation in both men and women. When compared with low job strain, active work (high-psychological demand and high-decision latitude) and high job strain were associated among men with a significantly higher level of social isolation. This study shows that a change in psychosocial work conditions (demand and control) had an impact on social isolation and that this impact may be more significant in male workers than in female workers.

Cohort Studies↗

PubMed1975

Incentive motivation and behavioral inhibition in socially-isolated rats.

Rats reared from weaning in social isolation made more lever presses than controls on an alternating two-lever DRL schedule of reinforcement, and obtained fewer rewards. Isolates showed an increased tendency both to anticipate reward on the correct lever, and to perseverate on the lever which last gave reward, but their anticipatory deficit was relatively more marked. It is suggested that isolates act as if under an effectively higher level of food motivation. Measurement of home-cage food intake showed that the normal day-time depression of food intake was less marked in isolates than in socially-grouped animals.

Animals↗

PubMed1983

Social isolation: effects on pain threshold and stress-induced analgesia.

Individually housed DBA/2 mice showed higher pain thresholds than grouped mice. Stress-induced analgesia was evident in grouped but not in isolated mice. Since also morphine injections did not result in analgesic effects in isolated mice, it is suggested that social isolation results in an increased release of opioids which may produce a decreased sensitivity at the opiate receptor level. The role of endogenous opioids in relation to social isolation is discussed.

Animals↗

PubMed2004

Long-term social isolation and medial prefrontal cortex: dopaminergic and cholinergic neurotransmission.

Rearing rats in social isolation has been suggested as an animal model of schizophrenia, based mainly on the similarity between the attenuation of prepulse inhibition (PPI) in isolated rats and in schizophrenic patients. The medial prefrontal cortex (mPFC) plays a major role in the pathophysiology of schizophrenia. Thus, a postmortem micropunch analysis measuring dopamine (DA), DOPAC (3,4-dihydroxyphenylacetic acid) and homovanillic acid (HVA) in the dorsal and ventral subregion of the mPFC, the caudate putamen (CPu) and nucleus accumbens (NAc) was carried out on socially isolated or group-housed male Sprague-Dawley (SD) rats. Additionally, in vivo microdialysis with D-amphetamine (1 mg/kg ip) stimulation was performed in isolated animals and their controls, examining the ventral mPFC for acetylcholine (ACh), DOPAC and HVA levels. Simultaneously, recording of motor activity was performed. In the neurochemical postmortem tissue analysis we found no difference in any of the brain regions tested between isolated and group-reared animals. Amphetamine increased ACh levels in the mPFC, induced a decrease in DOPAC and HVA levels, and increased motor activity. A close to significant Drug x Housing interaction reflected the fact that the amphetamine-induced decrease of DOPAC was confined to the group-housed animals. In conclusion, social isolation leads only to moderate changes in the dopaminergic system in the mPFC, whereas the cholinergic system remains unaffected.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1991

Endogenous opioids: do they modulate the rat pup's response to social isolation?

Previous studies with several different species have suggested that opioids and their receptors are involved in the mediation of the infant's vocal response to social isolation. In the case of the rat pup, 2 models have been hypothesized to relate opioids and the ultrasonic call emitted during social isolation. One model views the comforting effects of social contact as opioid mediated and the apparent distress of social isolation as analogous to opiate withdrawal. The 2nd model considers social separation as a stressor that recruits endogenous opioids. This article describes 3 experiments that tested both of these models in 7-10-day-old rat pups. In Experiment 1, morphine (0.04-0.40 mg/kg) decreased the rate of isolation calls in a dose-dependent, naloxone-reversible fashion. However, the decrease in calling rate was observed only at doses that decreased locomotor activity. Administration of the reversible opiate antagonist naloxone (0.05-5.0 mg/kg) did not alter the rate of calls during either 2- or 6-min isolation tests at either 24 or 32 degrees C. In Experiment 2, the irreversible mu opioid receptor antagonist beta-funaltrexamine (beta-FNA) was administered into the lateral ventricle of 6-day-old pups. Again, no change in the rate of isolation calls was found, although sensitivity to morphine was markedly decreased, and mu (but not delta or kappa) receptors were decreased in selected brain regions by about 40%. In Experiment 3, in vivo receptor binding was used to directly investigate the availability of mu opioid receptors during social contact and social isolation. Pups injected with 3H-diprenorphine showed relatively high levels of specific in vivo binding that followed the regional pattern of in vitro binding, but no effects of social isolation were apparent in the 5 brain regions assayed. Taken together, the consistent negative results with opiate receptor antagonists, as well as the inability to detect an alteration of in vivo binding, suggest that the mu opioid receptor is not an essential part of the rat pup's vocal response to social separation.

Animals↗

PubMed2006

Effects of stress on catecholamine stores in central and peripheral tissues of long-term socially isolated rats.

Both the peripheral sympatho-adrenomedullary and central catecholaminergic systems are activated by various psycho-social and physical stressors. Catecholamine stores in the hypothalamus, hippocampus, adrenal glands, and heart auricles of long-term socially isolated (21 days) and control 3-month-old male Wistar rats, as well as their response to immobilization of all 4 limbs and head fixed for 2 h and cold stress (4 degrees C, 2 h), were studied. A simultaneous single isotope radioenzymatic assay based on the conversion of catecholamines to the corresponding O-methylated derivatives by catechol-O-methyl-transferase in the presence of S-adenosyl-l-(3H-methyl)-methionine was used. The O-methylated derivatives were oxidized to 3H-vanilline and the radioactivity measured. Social isolation produced depletion of hypothalamic norepinephrine (about 18%) and hippocampal dopamine (about 20%) stores and no changes in peripheral tissues. Immobilization decreased catecholamine stores (approximately 39%) in central and peripheral tissues of control animals. However, in socially isolated rats, these reductions were observed only in the hippocampus and peripheral tissues. Cold did not affect hypothalamic catecholamine stores but reduced hippocampal dopamine (about 20%) as well as norepinephrine stores in peripheral tissues both in control and socially isolated rats, while epinephrine levels were unchanged. Thus, immobilization was more efficient in reducing catecholamine stores in control and chronically isolated rats compared to cold stress. The differences in rearing conditions appear to influence the response of adult animals to additional stress. In addition, the influence of previous exposure to a stressor on catecholaminergic activity in the brainstem depends on both the particular catecholaminergic area studied and the properties of additional acute stress. Therefore, the sensitivity of the catecholaminergic system to habituation appears to be tissue-specific.

Adrenal Glands↗

PubMed1999

Involvement of diazepam binding inhibitor and its fragment octadecaneuropeptide in social isolation stress-induced decrease in pentobarbital sleep in mice.

Diazepam binding inhibitor (DBI) and its fragment, octadecaneuropeptide (ODN), are putative endogenous ligands for benzodiazepine (BZD) receptors and have been shown to act as an inverse BZD receptor agonist in the brain. A previous study suggested that the social isolation stress-induced decrease in pentobarbital sleep in mice was partly due to endogenous substances with an inverse BZD receptor agonist-like property. In this study, we examined the effects of DBI and ODN on pentobarbital sleep in group-housed and socially isolated mice to test the possible involvement of DBI and ODN in a social isolation-induced decrease in pentobarbital sleep. The socially isolated mice showed significantly shorter durations of pentobarbital (50 mg/kg, intraperitoneally, i. p.) sleep compared to the group-housed animals. When injected intracerebroventricularly (i.c.v.), DBI and ODN (3 and 10 nmol) dose-dependently shortened the pentobarbital-induced sleeping time in group-housed mice at the same dose range, but these peptides had no effect on the sleeping time in socially isolated animals. In contrast, flumazenil (16.5-33 nmol, i.c.v.), a BZD receptor antagonist, reversed the pentobarbital sleeping time in socially isolated mice to the level of group-housed animals without affecting the sleeping time in group-housed animals. The effects of DBI and ODN in group-housed mice were significantly blocked by flumazenil (33 nmol, i.c.v.). Moreover, the effect of flumazenil in socially isolated mice was significantly attenuated by DBI and ODN (10 nmol, i.c.v.). These results suggest that the changes in the activity of DBI and/or ODN are partly involved in the social isolation-induced decrease in the hypnotic action of pentobarbital in mice.

Animals↗

PubMed2005

Social isolation rearing affects prefrontal cortical response to ventral tegmental area stimulation.

BACKGROUND: Animals reared in social isolation exhibit attentional deficits that parallel those found in schizophrenia patients. Such disturbances are frequently attributed to a dysfunction of the mesocortical system. Here we investigated whether electrophysiologic characteristics of prefrontal cortical pyramidal neurons or mesocortical responses were changed in isolated animals. METHODS: In vivo intracellular recordings were obtained from prefrontal cortical pyramidal neurons in animals raised in social isolation or in socialized control animals before and after ventral tegmental area stimulation mimicking dopamine cell burst firing. RESULTS: Prefrontal cortical pyramidal neurons recorded from isolated animals showed bimodal characteristics resembling those of their socialized littermates. Stimulation of the ventral tegmental area evoked plateau depolarizations in both groups, but this was accompanied by abnormal firing or a short hyperpolarization in most of the isolated animals. CONCLUSION: These findings suggest that social isolation rearing may affect mesocortical information processing.

Animals↗

PubMed2000

Social isolation stress enhanced liver metastasis of murine colon 26-L5 carcinoma cells by suppressing immune responses in mice.

We investigated the effect of social isolation stress on the formation of experimental liver metastasis resulted from intraportal vein (i.p.v.) injection of colon 26-L5 carcinoma cells in male Balb/c mice, and elucidated some of the underlying mechanism involving the effects of this stress on cellular immunity. Increases in the colony number and tumor burden were observed in the mice socially isolated before and/or after tumor cell challenge, as compared with the group-housed mice. In addition, exposure of mice to 2 weeks of preisolation resulted in decreases in the thymus weight and number of thymocytes by 35.8% and 40.2%, respectively, in comparison with the controls. Reduced proliferative response of splenocytes to various stimuli and suppressed splenic NK activity, as well as decreased macrophage-mediated cytotoxicity, were also found in the mice exposed to social isolation. Thus, these results suggest that social isolation stress enhances tumor metastasis in part via its suppressive effect on the immune system of the host.

Animals↗

PubMed1980

Social isolation in lung cancer patients.

Lung cancer patients were found to score significantly higher on a social isolation scale when compared to a group of patients with other chronic lung diseases as well as to a control group of apparently healthy adults. Social isolation in lung cancer patients did not correlate with their apparent isolation, depression or with their physicians' estimations of their attitudes. Social workers involved in the care of lung cancer patients should be aware that these patients may be actually, if not obviously, socially isolated.

Depression↗

PubMed1994

Social isolation in the rat produces developmentally specific deficits in prepulse inhibition of the acoustic startle response without disrupting latent inhibition.

A series of experiments examined the effects of 8 weeks of social isolation on spontaneous locomotor activity, prepulse inhibition (PPI) of the acoustic startle response, latent inhibition (LI) in a conditioned suppression paradigm, and basal and d-amphetamine stimulated dopamine (DA) release in the ventral striatum, as measured by in vivo microdialysis. Both isolation-reared animals (those isolated from the weaning age) and isolation-housed animals (those isolated as adults) were hyperactive when placed in a novel environment. Social isolation also led to deficits in PPI of the acoustic startle response that were specific to isolation-reared animals. Isolation rearing was without effect on the expression of LI but did lead to an enhanced response to systemic d-amphetamine in terms of striatal DA release. The data are discussed with respect to the involvement of ventral striatal DA mechanisms in the expression of PPI and LI, differences in the impact of social isolation in young and adult animals, and the utility of social isolation model as a nonlesion, nonpharmacologic means of perturbing ventral striatal DA function.

Acoustic Stimulation↗

PubMed2006

An examination of the social networks and social isolation in older and younger adults living with HIV/AIDS.

This study examined social networks and social isolation in older (50 years or more) and younger (ages 20 to 39) adults with HIV/AIDS. The author conducted interviews with 88 individuals living with HIV/AIDS in the Pacific Northwest. Both groups' social networks had similar patterns; however, older adults were more likely to live alone. More than 38 percent of older adults and 54 percent of older adults of color were at risk of social isolation compared with 25 percent of those 20 to 39 years of age. Older men and older adults of color had significantly lower scores on the social network scale than others. Having a confidant and receiving instrumental support were significantly correlated with reduced HIV stigma. Implications for social work practitioners are discussed.

Adult↗

PubMed1985

Relationship in very elderly veterans of nutritional status, self-perceived chewing ability, dental status, and social isolation.

The relationship of nutritional status, self-perceived chewing ability, dental status, and social isolation was examined. Seventy-three ambulatory, elderly (means = 86 years) veterans were studied. Parameters of nutritional status included intakes of protein, carbohydrate, fat, and total calories, and hemoglobin, serum albumin, total lymphocyte count, and height/weight ratio were determined. Dental status was measured, and self-perceived chewing problems and social isolation were assessed by interview. Results showed a significant correlation between perceived chewing problems and diminished protein and total caloric intake and increased carbohydrate intake. No association was found between measured dental status and nutritional status. Social isolation was weakly correlated with greater protein and calorie intake. These results support the contention that the presence of self-perceived chewing problems are more reliable than the quality of the dentition itself as an indicator of altered nutritional status.

Aged↗

PubMed2004

Changes in levels of social isolation and loneliness among older people in a rural area: a twenty-year longitudinal study.

The Bangor Longitudinal Study of Ageing (BLSA), conducted in rural Wales from 1979 to 1999, followed a cohort of survivors from more than 500 people over 20 years. Using both quantitative and qualitative data from the study, the factors associated with increases and decreases in loneliness and social isolation were identified. The study was based on a population sample and survivors were followed up every 4 years. From 1983 to 1987, 30 people aged 75 and over in 1979 were studied intensively. The customary measure of loneliness was used, as well as an aggregate measure devised by the research team. Social isolation was similarly measured, using an aggregate measure. Respondents were assessed as demonstrating low, moderate, or high levels of loneliness or isolation. Subsequently, statistical models of loneliness and social isolation were developed. Some respondents were assessed as not experiencing social isolation or loneliness during the study. Others showed changes in levels. In this article, the data are explored, seeking factors associated with changes in social isolation and loneliness. Outcome measures of these two variables of interest are compared with items from the aggregate measures and other identifiable intervening variables. The article discusses which change variables contribute most to levels of isolation and loneliness and result in different combinations of these two outcomes. Implications for policy and practice are discussed.

Aged↗

PubMed1999

Diazepam binding inhibitor (DBI) gene expression in the brains of socially isolated and group-housed mice.

Diazepam binding inhibitor (DBI), a putative endogenous polypeptide ligand for benzodiazepine (BZD) receptors, has been shown to act as an inverse BZD receptor agonist in the brain. We previously suggested that the social isolation stress-induced decrease in pentobarbital sleeping time in mice was partly due to an increase in the activity of endogenous substances with an inverse BZD receptor agonist-like property such as DBI. In this study, we examined whether the DBI gene expression is affected by socially isolated stress. Consistent with the previous findings, the in situ hybridization result showed very strong signals of DBI mRNA around the regions of the third ventricle, especially the lining cells, the arcuate nucleus of the hypothalamus and the cerebellum, in both socially isolated and group-housed animals. Unexpectedly, however, semi-quantitative experiments with reverse transcription polymerase chain reaction technique revealed that socially isolated mice had significantly less expression of DBI mRNA in the hypothalamus than group-housed animals, and no difference in the expression in the other brain areas was observed between two animal groups. We discuss the relationship between the decrease of DBI mRNA expression in the hypothalamus and the decrease of GABA(A) receptor function following long-term social isolation in mice.

Acyl Coenzyme A↗

PubMed1982

Hearing impairment and social isolation in the elderly.

This investigation was conducted to determine the relationship between hearing impairment and social isolation in a sample of community-based individuals over age 65. Each subject reported first noting a hearing loss after age 53. In all cases the hearing loss was insidious in onset and of unknown etiology. All subjects underwent a complete audiological evaluation. This included pure-tone testing, speech discrimination testing, and self-assessed hearing handicap. Further, responses were obtained to scales which measured quantitatively the degree of subjective and objective social isolation. Each of the correlations between the Objective and Subjective Social Isolation Scale scores and the audiologic variables was statistically significant. The audiologic measures were more strongly correlated with the subjective than with the objective isolation measures. The Hearing Measurement Scale (HMS) score explained the greatest and the W-22 score the smallest proportion of the variance in each of the isolation scale scores.

Aged↗

PubMed1982

Hyperactivity and obesity: the interaction of social isolation and cafeteria feeding.

Rats were reared in social isolation or in social groups of 4 or 5 rats per cage from weaning and were fed either a lab chow diet or a diet of 4 palatable foods (cafeteria diet), in addition to the lab chow. The hyperactivity of isolation-reared rats appears to be a reactivity to novel environmental stimuli, since it was seen only in the 0.5 hr tests and not in the near 24 hr test. It was found that hyperactivity and increased body weight can develop within as few as 7 to 10 days in rats reared in isolation from weaning. Cafeteria feeding enhanced activity in isolation-reared rats, but suppressed it in group-reared rats. Isolation-reared rats fed a cafeteria diet had strong, stable preferences for their most preferred food over the 25 days of measurement. Rats reared in isolation had significantly different food preferences, as compared with rats reared in groups. Cafeteria fed rats had a significantly greater calorie intake and body weight than rats fed lab chow. On analysis, cafeteria fed rats had significantly greater carcass energy and an increased amount of parametrial white adipose tissue as compared with rats fed only lab chow. The interscapular brown adipose tissue (IBAT) weights of cafeteria fed rats were also greater. However, as there was no difference between the cafeteria and chow fed rats in the total amount of protein in the IBAT, it was concluded that the increased weight of the IBAT did not reflect a genuine hypertrophy of the tissue.

Adipose Tissue, Brown↗